Carnival-goers have been warned to stay safe in the record-breaking bank holiday heat ahead of the second day of celebration in Notting Hill.
Several people were treated for dehydration as temperatures soared to between 32C and 33C - thought to be the hottest Notting Hill Carnival ever - as the annual celebration opened on Sunday.
Almost 100 people had been arrested by late evening, the Metropolitan Police said, for offences including assaulting officers, possession of offensive weapons and drug offences.
One million people are expected to enjoy the carnival over the course of the two days.
London Ambulance Service advised people to drink responsibly if consuming alcohol and to drink plenty of water.
On Sunday, they tweeted: "We are busy at #NottingHillCarnival this evening treating lots of patients, many of whom are intoxicated or haven't kept hydrated in this heat. You can help us by please stepping to one side if you see us making our way through the crowds to/with a patient."
Meteorologist Steven Keates said: "It's looking like this is one of the hottest carnivals ever."
The Met Office said similarly high temperatures are expected on Monday. While the dates of carnival were not fixed in the early days, it has been held on the late August bank holiday weekend for at least four decades, organisers said.
By 10pm on Sunday, 97 people had been arrested.
Eleven police officers were injured and needed medical attention, with 12 people arrested on suspicion of assaulting police.
Among the other arrests were 41 people in relation to drug offences, nine for possession of an offensive weapon and three for sexual offences.
Almost 12,500 police officers and some 1,000 stewards will be in place across the two days.